Sega Genesis Booloader
By Joseph Norman
http://devster.netfirms.com

Intro
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A Sega Genesis bootloader to test out programs sent to a real Sega using RS232. It's made to be burned onto an eprom strapped onto a cartridge. You can send files to the Sega via X-Modem RS232, and it will save the file into ram starting at $FF0000, and then it will execute it. It uses the RS232 on the expansion port of the Sega. The Sega I/O's are TTL level, so you will need a MAX233 or such so the TTL levels are converted to RS232 level. Files are recieved at 4800 bps, no parity, 8 data bits, 1 stop bit, and no flow control. Oh, if you have a Sega Genesis version 2 or above, you will need to change the base value of the serial port because newer Segas don't have an expansion port.

EXTENSION PORT          PIN     FUNC
PINOUT                  ----------------
                        1       VCC
                        2       RIGHT
                        3       LEFT
                        4       DOWN
                        5       UP
                        6       TR (SERIAL RECIEVE)
                        7       GND
                        8       TH (INTERUPTER)
                        9       TL (SERIAL SEND)